This is the part that you have to get 100% correct if you want to have a successful SEO campaign. What you have to remember is:
Don't write for the search engines
Don't write for the search engines! When we teach people SEO some go away and write an article 500 words long that is rammed full of keywords, makes no sense and in all honesty looks ridiculous. If a potential client was to land on such a page they would leave instantly thinking you were some kind of idiot, so make sure you write an article that sells your product or services to the best of your ability. Of course you should be mentioning the keyword in there several times, but there is no right or wrong answer here, it doesn't have to be in there 8 times on a 500 word article. If it reads well and is only mentioned 4 or 5 times then so be it, you basically have to show the search engines what the article is about so it does have to be mentioned but not excessively.
Don't copy and paste other peoples content
I personally think the same as everyone else, I'd love a shortcut, a freebie, call it what you like, I don't like sitting having to write our own content. I'd love to steal someone else's and use the good bits they have used, however in this day and age, Google can very quickly detect duplicate content and they will penalise those who attempt it.
There are tools to check whether or not content has been copied, Google " Copyscape " or go to this link: www.copyscape.com
Where it asks for a URL stick in your own URL and see if it flags up anything. If you have copied and pasted, or even copied someone's content and tweaked a few words here and there then that's not good enough. You need to go away and do your own original piece. I understand there is only so many ways you can say something about a service or product, but make it as unique as possible because if you don't then you will basically be filtered out and the page or post that you have copied and pasted simply won't rank. If that becomes the case then its highly unlikely you will get any business from your website which in turn means you have wasted a load of time and possibly money getting this idea off the ground.
Only people who have put in some hard graft, time and effort rank well, there really are no shortcuts, I have looked for many years and have still yet to find one. There aren't a whole load of people that are committed to the cause or doing SEO properly as so many people want a shortcut or they are just too lazy. You can quickly catch up with these people by putting unique, well-written content on the website to kick off your onsite SEO.